Question

In the shown mass pulley system, pulleys and string are massless. The one end of the string is pulled by the force F=2mg. The acceleration of the block will be

Answer 1

Answer:

3g

Explanation:

1)  Let the tension in the string attached to the Force be T.

Then, T=F=2mg

2) Now,

As shown in figure attached,

Using Force equation,

2T-mg=ma

=>2*2mg-mg=ma

=>4mg-mg=ma

=>3mg=ma

=>a=3g

Hence, the acceleration of block of mass 'm' is 3g in upward direction.

Answer 2

Explanation:

T = 2mg

2T - mg = ma

2 × 2mg - mg = ma

4mg - mg = ma

3mg = ma

3g = a